After that, benefits would have to drop off sharply but wouldn't disappear. Now that assumes that Social Security will draw on its "trust fund" in 10 years, and there's a debate over whether that's real money.

(Because the trust fund is invested in special Treasury bonds - payable by the government - taxpayers will still foot the bill.)

But the trust fund does represent a serious promise to future retirees, and that's not easy for politicians to back away from. If benefits are reduced, those closest to retirement will likely take the smallest hit.

If you are already 55 or over, you're safe - the President took your benefits off the negotiating table, and it's hard to imagine future leaders taking a tougher line.

One much-discussed plan would simply slow the rate of benefits growth, which would the cut the Social Security checks of the youngest boomers by roughly 15% if enacted soon. But benefit cuts aren't the only possible fix: Taxes could go up instead.